David Haye has wanted to become world heavyweight boxing champion since he was seven years old, living in an 18th-floor council flat in Bermondsey, south-east London. A week tomorrow in Nuremberg, south-east Germany, he finally gets a shot at a version of the title. Standing squarely between the 29-year-old and the realisation of his long-cherished ambition, however, will be the WBA champion, Russian giant Nikolai Valuev, 7ft 2in and 23st of solid, hairy and, according to Haye, not particularly sweet-smelling flesh.

I last interviewed Haye six months ago, when he was due to fight the 6ft 7in Ukrainian Wladimir Klitschko, the IBF, WBO and IBO champion. He had just caused a stir by wearing a T-shirt depicting him triumphantly holding up the severed heads of Wladimir and Wladimir's brother Vitali, the WBC champ. The fight didn't happen because "The Hayemaker" strained his back, so this time, looking anew for headline fodder, he has loudly raised the issue of Valuev's body odour. "All that matted hair and sweat," he says, disdainfully. "People who've fought him before have noticed it, so I'm not looking forward to that too much." He is making rather a habit of offending big blokes from the former Soviet Union.

Haye, a comparatively petit fellow of 6ft 3in and 16st, who was undisputed world cruiserweight champion until he stepped up to heavyweight, has also described Valuev as a "monster" and a "freak show" of a human being. But of course there is method in his manners. "I do and say whatever I can to get under their skin," he says. "The more angry they are on the night, the less they think about their technique." It was a tactic similarly adopted by one of his heroes, Muhammad Ali. Joe Frazier and George Foreman were properly riled by Ali's often boorish taunts and insults which, in the Thriller in Manila and the Rumble in the Jungle, he duly backed up with his fists. Boorishness is all very well, but you have to win. What if Haye fails to win?

"It's not an option," he says. "I know that if I bob when I should weave, duck when I should dive, he'll take me out, so it needs to be a punch-perfect performance. But I know what it's like to lose, and I've vowed never to lose again. I can't allow anything I do to result in a loss. If necessary I'll fight like a dog to beat this guy."

Haye leans forward in his chair, in the Riverside Plaza, a smart London hotel close to his Vauxhall gym, and drops his voice slightly, as if to emphasise the significance of what he is saying.

"There are different ways to victory," he adds, "and if one strategy doesn't work then it will be a case of, 'What's the next strategy?' He's very effective at what he does. He's lost one in 52, he's beat some respected fighters, and they all said he was better than they expected. There are certain people you can't knock out with one shot and he's one of them, but everybody's got a weak point. I know it's not his head, but I'll find it. I will hit him more often than he's ever been hit before. I will work his body, his arms, his neck, anything available. And I will make him look stupid by missing a lot. I will dishearten him. Don't forget he's got no amateur pedigree to feed off. I learnt my craft as an international amateur, and that will help me beat him."

It is a stirring statement of intent, and to be sure, there's much more to heavyweight boxing than size and strength, but all the same, Valuev will enjoy a massive 10-inch superiority in reach. The fight is cutely billed as David v Goliath, but Haye's biblical namesake had a slingshot. And if Valuev does land one of his thunderous right hands, will the Haye chin stand up to it? That is the big question mark the Londoner carries into the ring. He has lost only once in 23 fights, and all but one of those 22 wins have been knockouts. Nobody doubts his own punching power. But can he take a punch?

"I think I can. I was knocked down a few times in the cruiserweight division, but always by someone smaller. You see it in boxing time and again. Manny Pacquiao got knocked out at flyweight, but Ricky Hatton couldn't hurt him [at light welterweight]. The shots that hurt you are the shots you don't see, and the lighter the other guy the faster his shots are. When you see it coming you brace it, block it, ride it, parry it, and those options are increased against heavyweights."

Capitalising on an opponent's weight is a strategy recommended by his father Deron, a panel beater by trade but also a martial arts instructor. And Deron's guidance extended to other, more important aspects of life. "He was the best kind of male role model," says Haye. "He was clean-living, always came straight home after work, very athletic. A lot of kids follow what their old man does, and with him it was all about health and fitness. There were people in my class at school who ended up banged up, shot, killed even. My parents led me away from that side of things, and so did boxing. I wasn't smoking weed or drinking, because it would have hurt my boxing."

He was only two or three, he adds, when his father recognised a precocious ability to throw a punch. "My dad used to say to his pals, 'Let my son punch your hand', and they couldn't believe my power. I've always had a freakish gift of being able to whack things." And people, of course, which came in handy when he was 11 and in his first year at secondary school. "The hardest kid in the school was this lad called Danny Robinson, a few years older than me. He tried to give me some grief and I bashed him up. Then he came over to me in the football cage later that same day, with a couple of his mates, and I did him again." A chuckle. "I saw him again a few years ago and we had a laugh about it."

Still, decking Danny Robinson in the football cage is one thing, decking Nikolai Valuev in the Nuremberg Arena quite another. How carefully has he studied footage of Valuev's 52 fights? "I've looked at some of them, of course. But it's a mistake, and one I've made in the past, to try to figure a fighter out by watching someone else fight him. It's like watching a football team. They do different things when they play your team. I've learnt a lot from watching tapes of Ali, Sugar Ray Leonard, Floyd Mayweather, and especially Roy Jones Jnr in his prime. He's the biggest inspiration to me, him and Lennox Lewis. Everyone has his own style, but nobody ever fights the same fight twice and Roy Jones was a master at those subtle adjustments, the pivoting of the feet, the head movement..."

As he says, though, that was Jones in his prime. At 40 the once great Floridian is still scrapping on, a shadow of his former self, and Haye abhors the spectacle of a boxer undermining his own legacy. "He could have retired as one of the all-time greats. He would have been in my top three of all time, no question. He went up to heavyweight and beat John Ruiz convincingly, but then he dropped back down to light heavyweight, got knocked out, Calzaghe beat him, and I just don't understand the motivation for carrying on. You've secured your legacy, you've got enough dough, why carry on?"

It is the perplexing, perennial boxing question, and Haye is determined that nobody will ever ask it of him. He says it was his intention even as a boy not to fight beyond the age of 30, and before he turns 31 in October 2011, he will honour his pledge to himself by quitting, as undefeated world heavyweight champion with two or three successful defences to his name, to be followed by a glittering career as a promoter if all goes perfectly to plan. On the other hand, no sport makes a mockery of plans quite like boxing does, and Haye is bright enough to know it, even if he won't admit it.

Can he honestly not envisage, eight or nine months from now, fancying one more pay day? "No," he says flatly. "I'm not a big spender, and anyway, how much money can one person spend? I've got a few cars. There's nothing I want to buy that I haven't got already."

I noticed one of his cars, a sporty Mercedes with a personalised number plate, when I arrived at the Riverside Plaza. In truth, it was hard not to notice, for it was parked somewhat ostentatiously across the entrance. And therein, perhaps, lies the contradictory essence of David Haye. He likes the expensive trappings of sporting success, and likes to show them off, but he doesn't crave any more of them and lives fairly modestly, in Brixton. He wants nothing more than to be heavyweight champion of the world, but he's happy for his reign to be brief. He is a smart, engaging, witty charmer, who can also descend to the level of the playground, as with his "you're ugly, you stink" insults. And he is keenly aware of his own eloquence, yet content in his own company.

This time next week, he tells me, solitude will be key to his preparation. "I try not to talk to many people before a fight because everyone wants to give you an opinion," he says. "I'll send and receive a few texts, but you get silly advice, like 'use your jab'. Oh yeah, I wasn't going to do that, thanks for telling me. Then I'll wake up on the day a bit earlier than usual, because of the adrenalin, and I'll think immediately, 'I'm going to have a tear-up tonight'. It's a strange feeling, because all those niggles and aches you've had, they all seem to disappear on the day. And then I'll just stay as relaxed as possible. I'll listen to Al Green, Otis Redding, Marvin Gaye, that sort of thing, and use as little mental and physical energy as possible. I'll save all the fast-twitch stuff for the last hour or two."

And what does he expect to dream about the night before the fight? What, indeed, did he dream about last night? "I dreamt about this big, massive, hairy body on the floor, and me standing over it." Funny, I had a feeling he might say that.

David Haye fights Nikolai Valuev for the WBA heavyweight title on 7 November, live on Sky Box Office (08442 410888)